Latch and detent assembly



July 7, 1959 W. L. CLIFTON, JR

LATCH AND DETENT ASSEMBLY 2 Sheets-Sheet 1 Filed Jun} 25. "1955 INVENTOR WALTER L. CLIFTON JR.

TTORNEYS y 1959 w. L. CLIFTON, JR 2,893,773

LATCH AND DETENT ASSEMBLY Filed July 25, 1955 2 Sheefs-Sheet 2 1N VENTOR I BY 71- 1", ,/Lm,

mTTORNEY WALTER L.CLIFTON JR.

United States Patent LATCH AND DETENT ASSEMBLY Walter L. Clifton, In, Atlanta, Ga., assignor to American Art Metals Company, Atlanta, Ga., a corporation of Delaware Application July 25, 1955, Serial No. 524,072

3 Claims. (Cl. 292-223) This invention relates to latches of the type used on exit doors and more particularly to a security latch including a detent device for preventing unauthorized unlatching movement of the latch mechanism, and to a door including such a latch.

The detent or locking device of this invention may be used with a panic latch assembly'of the type shown and described in my copending application Serial No. 387,182 entitled, Panic Latch, filed October 20, 1953, now Patent No. 2,805,091, issued September 3, 1957. The detent and locking device will be described as embodied in a door having the panic latch mechanism described in the application just mentioned.

An'object of this invention is to provide a detent or locking device for usewith a latch member to prevent unauthorized unlatching movement of the latch mechanism.

A further object of this invention is to provide a detent or locking device to prevent unauthorized unlatching movement of a panic latch of the type shown and described in my Patent No. 2,805,091.

A further object of the invention is to provide in combination with a panic latch assembly a detent or locking device which prevents unauthorized unlatching movement of the panic latch member but which permits the panic latch to be actuated to unlatched position by movement of the normal operating members for the panic latch.

. A further object of the invention is to provide a detent or'locking device for preventing unauthorized unlatching movement of a latch member which is automatically moved into detent or locking position upon closing movement of the door and which is automatically released from its detent or locking relation upon operation of the normal operating members for unlatching the latch member. I

In achievement of these objectives, there is provided in-accordance with an embodiment of this invention a detent member which is mounted in a hollow casing in the door stile adjacent a latch member which is pivotally movableinto latching engagement with a recess in the door frame. The detent member is carried by a spring biased support mounted on the door stile, the spring biased support normally tending to move the detent element into a position where it is disposedin the path of movement of the latch member and prevents movement of the latch member to unlatched position. A slidable cam element is spring biased to a position in which it engages the support for the detent element in such manner as to move the detent element out of locking or detent relation to the latch. The slidable cam element is engaged by the door frame upon closing movement of the door and is movedto a position in which it permits movement of the spring-biased detent to a position in which it is interposed in the path of movement of the latch member. A vertically movable operating means which engages the latch member to move the latch member to unlatched position engages the detent support when the operating member is moved inthe unlatching direction and is effective to thereby move the detent out of detent or locking relation to the latch member. The movement of the detent and its spring biased support by the latch operating means also permits the slidable cam member to be moved by its biasing spring back into a position which maintains the detent out of locking relation to the latch member until the slidable cam element again engages the door frame.

Further objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings in which:

Fig. 1 is a view in vertical section showing details of the panic door and of the panic latch mechanism carried thereby;

Fig. 2 is an enlarged view in vertical section of the upper end. of the panic latch mechanism showing details of the detent device of the invention;

Fig. 3 is a fragmentary top plan view of the panic door and of the panic latch mechanism mounted on the door;

Fig. 4 is a view in vertical section along line 4-4 of Fig. 2, showing the detent or locking member in locking relation to prevent movement of the latch member to unlatched position;

Fig. 5 is a fragmentary vertical section illustrating the position of the elements of the detent or locking mechanism when the detent or locking mechanism is maintained out of locking relation by its slidably movablecam element;

Fig. 6 is a view in vertical section along line 66 of Fig. 5; and v 1 Fig. 7 is a perspective view of the detent or locking mechanism detached from the door.

Referring now to the drawings, and more particularly to Figs. 1 and 3, there is shown a door frame 10 and a threshold 12 respectively having latch-accommodating slots 14 and 16. A door generally indicated at 18 is provided at its free edge with a hollow casing generally indicated at 20 for receiving the latch and its actuating mechanism. Casing 20 includes a pair of oppositely disposed sidewall portions 22 and 24 which are connected adjacent but spaced from their outer ends by a transversely extending web portion 26 which is provided with a slot indicated at 27 extending downwardly from its upper edge for a short distance. The end portions of casing walls 22 and 24 which project beyond web portion 26 define a channel which receives a detachable astragal 28. At the upper end of casing 20, a latch 30 is pivotally supported on pin 32 and is biased by a spring 34 in such manner that latch 30 normally tends to move upwardly through slot 14 to engage door frame 10 in latching relation. Latch 30 is in the shape of a bell crank and is provided with an arm 36 which extends downwardly from the pivotal axis 32 as best seen in Fig. l. A latch 38 similar to the latch 30 just described is provided at the lower end of the casing 20. The lower latch member 38 is spring biased into latching engagement with threshold 12 through the aperture 16 of the threshold and is provided with an arm 40 which extends upwardly from the pivotal axis of latch 38.

The operating mechanism for moving the latches 30 and 38 to unlatched position includes an operating lever gen: erally indicated at 42 mounted on the inside of the door and pivotally supported by bracket member 44 attached to the inner wall surface of the door 18. Operating lever 42 includes an actuating arm 46 which projects into the interior ofhollow casing 20 and through an apertured portion in a C-shaped yoke member indicated at 48 disposed 'on the interior of casing 20. Rod members 50 and 52 are rigidly attached to the upper and lower ends, respectively, of yoke member 48. At the upper end of 3 rod member 50 is rigidly attached a drag angle 54 anda 3 similar drag angle 56 is rigidly attached to the lower end of rod member 52. Rods 50 and 52 are guided for vertical movement within casing 20 by apertured bracket m mbe s .58. 16 6 and 4 Carried by easing 0.- A sp ng 6.6 easier be wee bracket 60 and t e upp nd ct iii e 4.8 and se o spr 5 d p e b we a ket 64 aud the upper .end .of angle member 56 cooperate the natural weight of the assembly to normally bias yoke 48 and the attached rod and angle members in a dowuwardor latching direction. Mounte d Within casing 20 below latch 30 is a bell crank lever generally indicated at 70 including an arm 72 which extends into a slot 74 in upper angle member 54. Bell crank 70 also includes an arm 76 which is movable into engagement with the downwardly extending arm 36 of latch member 30. In a similar manner, a bell crank lever generally indicated at 78 is supported at the lower end of casing 20 and includes an arm 80 which extends into a slot 82 in the vertically extending leg of angle member 56, and an arm 84 which is engageable with the upwardly extending leg .40 of latch member 38.

When the operating handle 42 on the inside of the door is pushed downwardly about its pivotal support, operating arm .46 which extends through a slot in shared yo e membe 4 e a t uppe e 4 o the s ot and raise yok me be 4 p a y h y causing angle member 54 at the upper end of the casing to rotate bell crank member 70 in a counterclockwise direction with respect to the view shown in Fig. 1 and ausing ang e mem t e lower e d f easing 20 to rota bell ank mem e 8 i a cl ck is di e o with respect to the view shown in Fig. 1. The rotation of the ,rcispcctive bell crank members 70 and 78 causes the respective latch members 30 and 38 to be pivotally moved in a clockwise and a counterclockwise direction, respectively, and thus to be retracted to unlatch position due to the engagement of hell crank members 70 and 78 with the latch members.

Yoke 48 may also be raised to move latch members 30 and 38 to unlatched position in the same manner as provided by operating member .42 by the use of a key inserted through the keyhole 86 on the outside of the door to rotate a camming device generally indicated at 88. Camming device 88 engages an abutment 90 which is fixed .to the upper portion of yoke 48 and raises yoke 90 and the attached rods 50 and 52 in the same manner as if operating member 42 were actuated.

All of the structure hereinbefore described is substantially the same as that described and illustrated in my Patent No. 2,805,091.

In the structure thus far described, it would be possible for a burglar or other person seeking unauthorized entry into the building to pivotally move the latch members 30 and 38 to unlatched position by inserting a knife or other similar object into engagement with these latch members from the outside of the building to pivotally move the latch members in an unlatching direction.

To prevent the unauthorized movement of latch member 30 to unlatched position and thus to prevent unauthorized opening of the door, the detent and locking device generally indicated at 100 in the drawings is provided in combination with the latching mechanism hereinbefore described. The detent and locking assembly 100 includes a mounting plate 102 which is adapted to be rigidly fixed by means of rivets or other suitable fastening means to the upper portion of web 26 of casing 20. Mounting plate 102 includes a right angle flange portion 103 which is substantially flush with the upper edge of web 26.

'Rigidly attached to the upper portion of mounting plate 102 by means of rivets 106 or other suitable fastening means is a flat resilient support member or spring plate. .108 for the detent or locking member, support member 1 35 ei g made of n opp r s e 9 t e meterial having a spring-like quality. Rivets 106 are arranged vertically along one side of spring plate 108 while the other side of support member 108 remains free to move but normally is urged by the resiliency of the material to lie in face to face engagement with mounting plate 102. Spring plate 108 is provided at its left-hand side with respect to the view shown in the drawings with an upwardly extending portion 110 which extends to a level closely adjacent but spaced from the upper edge of the support plate 102. The upwardly extending portion 110 is itself provided at the right-hand portion of its upper edge with a small tab-like projection 112 which extends upwardly a short distance above the remaining portion of the top edge of extension 110.

A detent or locking pin 114 is carried by the upper portion of extension 110 and extends inwardly through aligned apertures in mounting plate 102 and web 26 and into the hollow interior of casing 20 at a level such that the locking pin 114 lies on a level just slightly below the lower edge of latch 30 when latch 30 is in its latched position as shown in Fig. l, 2 and 4. Displaced vertically below detent 114 is a cam pin 116 which is rigidly attached to resilient support 108 and extends inwardly h o gh lisa r ures i mou t n Pl 0 a d eb 26 nto he path cf ang mem e Ql1 1. 6 y ng a o e the n mal, ne led lev of angle 5 n 6 is r vided with a bevel cam edge 118 which is engaged by the Upper edge of angle member 54 when angle 54 is raised due to the actuation of operating lever 42 or due to the operation of a key inserted through keyhole 86.

Rigidly attached to the upper portion of mounting plate 102 above the level of the main body portion of resilient support 108 is a cam guide member 120 which is adapted to guide the transversely sliding movement of a slidable cam support member generally indicated at 122. The cam guide member 120 has a forward wall portion 124 which extends into abutting relation to the underneath surface of horizontal flange portion 103 of mounting plate 102. A slot or recess is provided in back of forward wall portion 124 of the cam guide member to receive cam support member 122, the cam support memher being slidably movable along the flat edge 126 which forms the bottom surface of the slot or recess. Cam support: member 122 is provided at its right-hand end with respect to the view shown in the drawings with a pin-like projection 128. Wall 24 of casing 20 is apertured to permit passage therethrough of pin 128.

Member 122 is of generally rectangular cross section for approximately half of its length extending from the end adjacent pin 128, the cross-sectional area of this portion of member 122 being just slightly less than the area of guide slot 125. The left-hand half of the length of cam support member 122 has approximately the lower half of its height cut away to define a longitudinally extending recess 130 best seen in Figs. 2, 5 and 7. At the left-hand end of cam support member 122, cam element 132 extends downwardly. As best seen in Fig. 7, cam element 132 is flush with the rear surface of cam support member 122 but is spaced rearwardly of the forward longitudinal surface of the main body portion of cam support 122 by a distance approximately equal to onehalf the thickness of member 122. Cam element 132 is in effect a means for counterbiasing the resilient detent support 108 to move detent or locking pin 114 out of the path of latch 30.

In order to bias the cam support member 122 and cam car ed t ereby t wa th righ t p ct t t view shown in the drawings, a biasing spring 134 is provided. Spring 134 may be made of piano wire or other similar spring-like material. Spring 134 is bent into l -shape and has a horizontal leg 136 and a vertical leg 138. Horizontal leg 136 is retained in position in a recess behind the forward wall of a spring holder 140 attached t the owe end o moun n p a e 0 he pp nd f e ical le 3 is re eived a ot-. 42 in the r hthand portion of cam support 122 adjacent pin 128. A set screw 144 anchors spring 134 to mounting plate 102 at the bend where vertical leg 138 joins horizontal leg 136.

The operation of the detent and locking device 100 will now be described. When the door is in closed position, the parts are in the position shown in Figs. 2 and 4. The pin 128 carried by cam support member 122 engages the door frame and slides cam support member 122 to the left with respect to the views shown in the drawings to the position shown in Fig. 2 in which pin 128 is in retracted position Within casing 20 and the cam element 132 has moved over to the extreme left and to the left of projection 112 at the extreme upper end of resilient support 108. With the cam element 132 in this position, the natural resiliency of resilient support 108 causes the free or left-hand edge portion of resilient support 108 to move inwardly toward mounting plate 102 so that the entire surface of resilient support 108 lies in a single vertical plane. Slidable cam support 122 and cam element are prevented from moving back to the right due to the fact that projection 112 is interposed in the path of cam element 132. Detent pin 114 extends inwardly through apertures in mounting plate 102 and web 26 into the interior of casing 20 so as to lie below latch 30. Cam pin 116 which lies below detent pin 114 also projects inwardly into the interior of casing 20 through apertures in mounting plate 102 and web 26 so as to lie above the upper edge of angle member 54 as best seen in Fig. 4.

With the detent assembly 100 in the position just described, downward movement of latch member 30 out of latching position is prevented due to the presence of detent or locking pin 114 in the path of unlatching movement of latch member 30. Hence, unauthorized unlatching movement such as might be caused by a burglar prying latch member 30 with a knife from the exterior of the building is prevented.

With the door locked as shown and with the detent pin 114 preventing unlatching movement of latch 30, the latch 30 may be moved to unlatched position by use of the normal operating means. When operating handle 42 inside the door is moved downwardly to raise yoke 48 and rods 50 and 52 in an upward direction to actuate latch members 30 and 38 to unlatched position in the normal manner, angle member 54 is moved upwardly and engages cam edge 118 of cam pin 116 carried by resilient support 108. The engagement of angle 54 with cam pin 116 causes the free edge portion of resilient support 108 to be moved outwardly away from the plane of support plate 102. Detent pin 114 carried by resilient support 108 is thereby moved outwardly and out of the path of movement of latch 30 so that latch 30 is free to move downwardly to unlatched position. At the same time, the forward movement of resilient support 108 moves the topmost projection 112 of support 108 forwardly and permits biasing spring 134 to move cam support member 122 to the right, causing cam element 132 to move behind the surface of projection 112 to maintain resilient support 108 in the forward position to which it has just been moved by the engagement of angle member 54 with cam pin and to maintain locking pin 114 clear of the path of movement of latch 30. The elements of the detent assembly then assume the position shown in Fig. 5 in which cam element 132 lies behind the surface of projection 112 and pin 128 projects beyond casing 20. With the parts shown in the position of Fig. 5, the latch element 30 is free to move without restraint from the detent pin 114.

Detent pin 114 may also be released from locking engagement with respect to latch 30 by operation of a key inserted through keyhole 86. A key inserted through keyhole 86 rotates cam elements 88 into engagement with the abutment generally indicated at 90 rigidly attached to yoke 48 and raises the yoke assembly and angle member 54 in the same manner as though operating handle 42 were actuated. The movement thus imparted to angle 54 is effective to engage cam pin 116 to move resilient support 108 and thus to move detent pin 114 out of the path of latch 30 in the same manner as just described in connection with the actuation of operating handle 42.

With the parts as shown in Figs. 5 and 6, closing of the door causes pin member 128 carried by cam support 122 to engage door frame surface 146 (Fig. 5 thereby pushing cam support member 122 to the extreme left to the position shownin Fig. 2. This retracts cam element 132 from behind the surface of projection 112 on resilient support 108 and permits the resilient support to move inwardly to the position in Figs. 2 and 4 in which detent pin 114 again lies in thepath of unlatching movement of latch 30 and in which cam pin 116 lies in the path of upward movement of angle member 54.

It can be seen from the foregoing that there is provided in accordance with this invention a detent or locking device which cooperates with a latch member on a panic or exit door or the like to prevent unauthorized opening of the door when the door is latched but which is automatically rendered ineffective upon the actuation of the authorized operating devices for opening the door.

The locking device is completely automatic in its operation and is rendered effective to prevent unauthorized unlatching upon closing of the door and is rendered ineffective to prevent unlatching upon the actuation of the ordinary operating means for opening the door.

While there has been shown and described a particular embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without department from the invention and, therefore, it is aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as my invention is:

1. For use in combination with a door movable to and from a closed position and having a movably mounted latch member and a latch operating mechanism for moving the latch member in a single plane to and from a latching position; a mounting plate fixed to said door to lie in a plane paralleling and adjacent to the plane of movement of the latch member, a flat substantially planar plate resiliently deflecti ble in a direction substantially normal to the plane thereof and having one edge secured to said mounting plate, said flat plate normally lying in face-to-face engagement with the mounting plate, the mounting plate being interposed between the flat plate and the latch member, a second edge of the flat plate spaced from the one edge being movable upon deflection of said flat plate in a direction substantially normal to the plane of movement of the latch member, a detent mounted upon said flat plate adjacent the second edge thereof, said detent projecting into the path of movement of said latch member when said flat plate is in face-to-face engagement with said mounting plate and said latch member is in locked position, first cam means on said fiat plate engageable with said latch operating mechanism during unlatching movement thereof to deflect the flat plate so as to move said second edge thereof away from said mounting plate, thereby retracting said detent from the path of said latch member, second cam means movably mounted upon said mounting plate, spring means anchored to said mounting plate and connected to said second cam means normally biasing said second cam means when the latch is in unlocked position to a first position wherein said second cam means retains said flat plate deflected and said detent out of the path of movement of said latch member, and means connected to said second cam means and actuated upon movement of the door to its closed position for moving said second cam means against the bias of said spring means to a second position wherein said second cam means frees said flat plate for return to its normal position in faceto-face engagement with said mounting plate and with said detent interposed in the path of movement of said latch member.

2. The combination of claim 1, wherein said latch member is movable arcuately about a horizontal axis, said flat plate is vertically disposed on said mounting plate, and said detent projects horizontally through an opening in said mounting plate to closely underlie said latch member when the door is in its closed position and said latch member is in its locking position.

3. The combination of claim 1, wherein said first cam means is a pin carried by said fiat plate adjacent said second edge thereof and having a beveled edge contacted by said latch operating mechanism when said latch operating mechanism is moved to unlatch said latch member, contact between said beveled edge of said pin and said latch operating mechanism deflecting said fiat plate to retract said detent from the path of movement of said latch member, and said second cam means in its first position is interposed between said fiat plate and said mounting plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,514,528 Hurd Nov. 4, 1924 1,593,852 Shaw July 27, 1926 1,674,760 Carroll June 26, 1928 2,758,862 Endter Aug. 14, 1956 FOREIGN PATENTS 190,947 Switzerland May 31, 1937 191,850 Germany Oct. 17, 1907 

